Restoring operation of data storage systems at disaster recovery sites

ABSTRACT

A computer-implemented method, according to one embodiment, is for restoring operation of a data storage system at a disaster recovery site. The computer-implemented method includes: in response to a disaster event occurring at a primary site, receiving an inode list from a cloud storage site, and receiving configuration information from the cloud storage site. The cloud storage site includes a backup copy of data that is stored at the primary site. Moreover, the inode list and the configuration information are used to construct a filesystem at the disaster recovery site. The filesystem at the disaster recovery site does not include a copy of the data that is stored at the primary site, but rather the filesystem includes a plurality of metadata stubs. The filesystem is further used to satisfy I/O commands that are received.

BACKGROUND

The present invention relates to data storage systems, and morespecifically, this invention relates to the accelerated restoration ofdata storage system operation at a disaster recovery site.

Data consumption has grown rapidly, in part because data has beenincreasingly gathered by various processes and products such as mobiledevices, remote sensing devices, software logs, cameras, microphones,radio-frequency identification (RFID) readers and wireless sensornetworks. As data consumption continues to grow, so does the storagerequirements associated with actually maintaining this data. Similarly,data accessibility has also become increasingly desirable.

While on premise data storage configurations have had difficultyaccommodating these increases in data storage and data accessibility,cloud storage has been able to provide some relief. Cloud storage is amodel of data storage in which the digital data is stored in logicalpools which correspond to physical storage. The physical storage spansmultiple servers, and the physical environment is typically managed by ahost, e.g., cloud storage provider. These cloud storage providers areresponsible for keeping the data available and accessible, and thephysical environment protected and running. People and organizations buyor lease storage capacity from the providers to store user,organization, or application data. It follows that cloud storage can beimplemented in conjunction with on premise data storage configurationsin order to achieve a distributed data storage system.

SUMMARY

A computer-implemented method, according to one embodiment, is forrestoring operation of a data storage system at a disaster recoverysite. The computer-implemented method includes: in response to adisaster event occurring at a primary site, receiving an inode list froma cloud storage site, and receiving configuration information from thecloud storage site. The cloud storage site includes a backup copy ofdata that is stored at the primary site. Moreover, the inode list andthe configuration information are used to construct a filesystem at thedisaster recovery site. The filesystem at the disaster recovery sitedoes not include a copy of the data that is stored at the primary site,but rather the filesystem includes a plurality of metadata stubs. Thefilesystem is further used to satisfy input/output (I/O) commands thatare received.

A computer program product, according to another embodiment, is forrestoring operation of a data storage system at a disaster recoverysite. The computer program product includes a computer readable storagemedium having program instructions embodied therewith. Moreover, theprogram instructions are readable and/or executable by a processor tocause the processor to: perform the foregoing method.

A system, according to yet another embodiment, includes: a processor,and logic integrated with the processor, executable by the processor, orintegrated with and executable by the processor. The logic is configuredto: perform the foregoing method.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a network architecture, in accordance with one embodiment.

FIG. 2 is a representative hardware environment that may be associatedwith the servers and/or clients of FIG. 1, in accordance with oneembodiment.

FIG. 3 is a tiered data storage system in accordance with oneembodiment.

FIG. 4 is a partial representational view of a distributed data storagesystem in accordance with one embodiment.

FIG. 5A is a flowchart of a method in accordance with one embodiment.

FIG. 5B is an illustrative progression of a method in accordance withone embodiment.

FIG. 6A is a flowchart of a method in accordance with one embodiment.

FIG. 6B is a flowchart of sub-processes for one of the operations in themethod of FIG. 6A, in accordance with one embodiment.

FIG. 7 is a representational view of a cloud computing node inaccordance with one embodiment.

FIG. 8 is a representational view of a cloud computing environment inaccordance with one embodiment.

FIG. 9 is a representational view of abstraction model layers inaccordance with one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

The following description discloses several preferred embodiments ofsystems, methods and computer program products for restoring operationof data storage systems at disaster recovery sites. Various ones of theapproaches included herein only copy data to the disaster recovery siteswhich corresponds to received I/O commands, thereby achieving asignificant reduction in the processing delays, storage space, networkbandwidth consumption, etc. experienced in response to a disaster eventoccurring at the primary storage site. This is accomplished, at least inpart, because the filesystem at the disaster recovery site is specifiedas only including metadata stubs which consume only a fraction of thestorage space that the actual data corresponding thereto does, e.g., aswill be described in further detail below.

In one general embodiment, a computer-implemented method is forrestoring operation of a data storage system at a disaster recoverysite. The computer-implemented method includes: in response to adisaster event occurring at a primary site, receiving an inode list froma cloud storage site, and receiving configuration information from thecloud storage site. The cloud storage site includes a backup copy ofdata that is stored at the primary site. Moreover, the inode list andthe configuration information are used to construct a filesystem at thedisaster recovery site. The filesystem at the disaster recovery sitedoes not include a copy of the data that is stored at the primary site,but rather the filesystem includes a plurality of metadata stubs. Thefilesystem is further used to satisfy input/output (I/O) commands thatare received.

In another general embodiment, a computer program product is forrestoring operation of a data storage system at a disaster recoverysite. The computer program product includes a computer readable storagemedium having program instructions embodied therewith. Moreover, theprogram instructions are readable and/or executable by a processor tocause the processor to: perform the foregoing method.

In yet another general embodiment, a system includes: a processor, andlogic integrated with the processor, executable by the processor, orintegrated with and executable by the processor. The logic is configuredto: perform the foregoing method.

FIG. 1 illustrates an architecture 100, in accordance with oneembodiment. As shown in FIG. 1, a plurality of remote networks 102 areprovided including a first remote network 104 and a second remotenetwork 106. A gateway 101 may be coupled between the remote networks102 and a proximate network 108. In the context of the presentarchitecture 100, the networks 104, 106 may each take any formincluding, but not limited to a local area network (LAN), a wide areanetwork (WAN) such as the Internet, public switched telephone network(PSTN), internal telephone network, etc.

In use, the gateway 101 serves as an entrance point from the remotenetworks 102 to the proximate network 108. As such, the gateway 101 mayfunction as a router, which is capable of directing a given packet ofdata that arrives at the gateway 101, and a switch, which furnishes theactual path in and out of the gateway 101 for a given packet.

Further included is at least one data server 114 coupled to theproximate network 108, and which is accessible from the remote networks102 via the gateway 101. It should be noted that the data server(s) 114may include any type of computing device/groupware. Coupled to each dataserver 114 is a plurality of user devices 116. User devices 116 may alsobe connected directly through one of the networks 104, 106, 108. Suchuser devices 116 may include a desktop computer, lap-top computer,hand-held computer, printer or any other type of logic. It should benoted that a user device 111 may also be directly coupled to any of thenetworks, in one embodiment.

A peripheral 120 or series of peripherals 120, e.g., facsimile machines,printers, networked and/or local storage units or systems, etc., may becoupled to one or more of the networks 104, 106, 108. It should be notedthat databases and/or additional components may be utilized with, orintegrated into, any type of network element coupled to the networks104, 106, 108. In the context of the present description, a networkelement may refer to any component of a network.

According to some approaches, methods and systems described herein maybe implemented with and/or on virtual systems and/or systems whichemulate one or more other systems, such as a UNIX system which emulatesan IBM z/OS environment, a UNIX system which virtually hosts a MICROSOFTWINDOWS environment, a MICROSOFT WINDOWS system which emulates an IBMz/OS environment, etc. This virtualization and/or emulation may beenhanced through the use of VMWARE software, in some embodiments.

In more approaches, one or more networks 104, 106, 108, may represent acluster of systems commonly referred to as a “cloud.” In cloudcomputing, shared resources, such as processing power, peripherals,software, data, servers, etc., are provided to any system in the cloudin an on-demand relationship, thereby allowing access and distributionof services across many computing systems. Cloud computing typicallyinvolves an Internet connection between the systems operating in thecloud, but other techniques of connecting the systems may also be used.

FIG. 2 shows a representative hardware environment associated with auser device 116 and/or server 114 of FIG. 1, in accordance with oneembodiment. Such figure illustrates a typical hardware configuration ofa workstation having a central processing unit 210, such as amicroprocessor, and a number of other units interconnected via a systembus 212.

The workstation shown in FIG. 2 includes a Random Access Memory (RAM)214, Read Only Memory (ROM) 216, an I/O adapter 218 for connectingperipheral devices such as disk storage units 220 to the bus 212, a userinterface adapter 222 for connecting a keyboard 224, a mouse 226, aspeaker 228, a microphone 232, and/or other user interface devices suchas a touch screen and a digital camera (not shown) to the bus 212,communication adapter 234 for connecting the workstation to acommunication network 235 (e.g., a data processing network) and adisplay adapter 236 for connecting the bus 212 to a display device 238.

The workstation may have resident thereon an operating system such asthe Microsoft Windows® Operating System (OS), a MAC OS, a UNIX OS, etc.It will be appreciated that a preferred embodiment may also beimplemented on platforms and operating systems other than thosementioned. A preferred embodiment may be written using eXtensible MarkupLanguage (XML), C, and/or C++ language, or other programming languages,along with an object oriented programming methodology. Object orientedprogramming (OOP), which has become increasingly used to develop complexapplications, may be used.

Now referring to FIG. 3, a storage system 300 is shown according to oneembodiment. Note that some of the elements shown in FIG. 3 may beimplemented as hardware and/or software, according to variousembodiments. The storage system 300 may include a storage system manager312 for communicating with a plurality of media and/or drives on atleast one higher storage tier 302 and at least one lower storage tier306. The higher storage tier(s) 302 preferably may include one or morerandom access and/or direct access media 304, such as hard disks in harddisk drives (HDDs), non-volatile memory (NVM), solid state memory insolid state drives (SSDs), flash memory, SSD arrays, flash memoryarrays, etc., and/or others noted herein or known in the art. The lowerstorage tier(s) 306 may preferably include one or more lower performingstorage media 308, including sequential access media such as magnetictape in tape drives and/or optical media, slower accessing HDDs, sloweraccessing SSDs, etc., and/or others noted herein or known in the art.One or more additional storage tiers 316 may include any combination ofstorage memory media as desired by a designer of the system 300. Also,any of the higher storage tiers 302 and/or the lower storage tiers 306may include some combination of storage devices and/or storage media.

The storage system manager 312 may communicate with the drives and/orstorage media 304, 308 on the higher storage tier(s) 302 and lowerstorage tier(s) 306 through a network 310, such as a storage areanetwork (SAN), as shown in FIG. 3, or some other suitable network type.The storage system manager 312 may also communicate with one or morehost systems (not shown) through a host interface 314, which may or maynot be a part of the storage system manager 312. The storage systemmanager 312 and/or any other component of the storage system 300 may beimplemented in hardware and/or software, and may make use of a processor(not shown) for executing commands of a type known in the art, such as acentral processing unit (CPU), a field programmable gate array (FPGA),an application specific integrated circuit (ASIC), etc. Of course, anyarrangement of a storage system may be used, as will be apparent tothose of skill in the art upon reading the present description.

In more embodiments, the storage system 300 may include any number ofdata storage tiers, and may include the same or different storage memorymedia within each storage tier. For example, each data storage tier mayinclude the same type of storage memory media, such as HDDs, SSDs,sequential access media (tape in tape drives, optical disc in opticaldisc drives, etc.), direct access media (CD-ROM, DVD-ROM, etc.), or anycombination of media storage types. In one such configuration, a higherstorage tier 302, may include a majority of SSD storage media forstoring data in a higher performing storage environment, and remainingstorage tiers, including lower storage tier 306 and additional storagetiers 316 may include any combination of SSDs, HDDs, tape drives, etc.,for storing data in a lower performing storage environment. In this way,more frequently accessed data, data having a higher priority, dataneeding to be accessed more quickly, etc., may be stored to the higherstorage tier 302, while data not having one of these attributes may bestored to the additional storage tiers 316, including lower storage tier306. Of course, one of skill in the art, upon reading the presentdescriptions, may devise many other combinations of storage media typesto implement into different storage schemes, according to theembodiments presented herein.

According to some embodiments, the storage system (such as 300) mayinclude logic configured to receive a request to open a data set, logicconfigured to determine if the requested data set is stored to a lowerstorage tier 306 of a tiered data storage system 300 in multipleassociated portions, logic configured to move each associated portion ofthe requested data set to a higher storage tier 302 of the tiered datastorage system 300, and logic configured to assemble the requested dataset on the higher storage tier 302 of the tiered data storage system 300from the associated portions.

Of course, this logic may be implemented as a method on any deviceand/or system or as a computer program product, according to variousembodiments.

As previously mentioned, the continued growth of data consumption hasincreased the storage and data accessibility requirements associatedwith actually maintaining this data. While on premise data storageconfigurations have had difficulty accommodating these increases in datastorage and data accessibility, cloud storage has been able to providesome relief. Again, cloud storage is a model of data storage in whichthe digital data is stored in logical pools which correspond to physicalstorage. The physical storage spans multiple servers, and the physicalenvironment is typically managed by a host, e.g., cloud storageprovider. These cloud storage providers are responsible for keeping thedata available and accessible, and the physical environment protectedand running. People and organizations buy or lease storage capacity fromthe providers to store user, organization, or application data. Itfollows that cloud storage can be implemented in conjunction with onpremise data storage configurations in order to achieve a distributeddata storage system.

However, conventional implementations of such data storage systems havealso experienced a number of shortcomings. For instance, each locationin a data storage system stores a copy of the same data, therebysignificantly increasing data storage consumption. Moreover, continuallymoving data between each of the locations in a data storage systemconsumes a significant amount of computing resources and networkbandwidth.

In sharp contrast to these conventional shortcomings, various ones ofthe embodiments included herein are able to achieve distributed storagesystems which are capable of efficiently recovering from disaster eventsby reducing data loss as well as processing delays, e.g., as will bedescribed in further detail below.

FIG. 4 depicts a distributed data storage system 400, in accordance withone embodiment. As an option, the present distributed data storagesystem 400 may be implemented in conjunction with features from anyother embodiment listed herein, such as those described with referenceto the other FIGS. However, such distributed data storage system 400 andothers presented herein may be used in various applications and/or inpermutations which may or may not be specifically described in theillustrative embodiments listed herein. Further, the distributed datastorage system 400 presented herein may be used in any desiredenvironment. Thus FIG. 4 (and the other FIGS.) may be deemed to includeany possible permutation.

As shown, the distributed data storage system 400 includes a primarysite 402 which is coupled to a cloud storage site 404. The cloud storagesite 404 is also coupled to a disaster recovery site 406. The cloudstorage site 404 may be coupled to each of the primary site 402 and thedisaster recovery site 406 using any desired type of communicationconnection. For instance, in some approaches the cloud storage site 404is coupled to the primary site 402 and/or the disaster recovery site 406by a physical connection, e.g., such as a wired connection, a cable, alogical bus, etc. In other approaches, the cloud storage site 404 iscoupled to the primary site 402 and/or the disaster recovery site 406 bya wireless connection, e.g., such as a WAN. However, an illustrativelist of other network types which may couple the cloud storage site 404to the primary site 402 and/or the disaster recovery site 406 includes,but is not limited to, a LAN, a PSTN, a SAN, an internal telephonenetwork, etc. Accordingly, the cloud storage site 404 is able tocommunicate with the primary site 402 and the disaster recovery site 406regardless of the amount of separation which exists therebetween, e.g.,despite being positioned at different geographical locations.

The primary site 402, the cloud storage site 404, and the disasterrecovery site 406 each include a controller 408 which is in turn coupledto a data storage array 410. Each of the data storage arrays 410 furtherinclude a plurality of data storage components 412, e.g., such as HDDs,SSDs, magnetic tape drives, etc. The data storage components 412included in a given array 410 may each be the same or different fromeach other depending on the desired approach. Similarly, data storagecomponents 412 included at each of the sites 402, 404, 406 may be thesame or different from each other.

Referring still to FIG. 4, the primary site 402 is also coupled to auser 414. It follows that the primary site 402 is able to receive I/Ocommands from the user 414 and satisfy them using the controller 408 aswell as the data in the data storage components 412. As a result, thecontroller 408 and data storage array 410 at the primary site 402 areable to maintain a filesystem which includes data that remainsaccessible to the user 414.

The data that is stored at the primary site 402, along with the metadataassociated therewith, is preferably replicated at the cloud storage site404, thereby forming a secondary copy of the filesystem which exists atthe primary site 402. Moreover, as data is added to, modified at,removed from, etc., the primary site 402, these changes are alsoreplicated to the cloud storage site 404. In some approaches, thedistributed data storage system 400 implements one or more data storageschemes which are able to provide hybrid cloud storage capability.According to an example, which is in no way intended to limit theinvention, the distributed data storage system 400 implementstransparent cloud tiering which enables usage of cloud object storage(e.g., public, private, on-premises, etc.) as a secure, reliable,transparent storage tier. Implementing transparent cloud tiering isparticularly desirable in some approaches by leveraging existinginformation lifecycle management policy language semantics, therebyallowing administrators to define policies for tiering data to a cloudobject storage.

It follows that the cloud storage site 404 is able to maintain anupdated copy of the data stored at the primary site 402 which isinsulated from any issues which occur at the primary site 402, e.g.,such as a disaster event. For instance, in a multi-site data storagesystem configuration such as that illustrated in FIG. 4 which includes aprimary site 402 and a cloud storage site 404, even if the primary site402 goes offline, a copy of the data (e.g., files) is still stored atthe cloud storage site 404. Further still, data stored at the cloudstorage site 404 may be used to establish a secondary filesystem at thedisaster recovery site 406 while the primary site 402 remains offline,e.g., as will be described in further detail below.

Replicating the data stored at the primary site 402 to the cloud storagesite 404 is an ongoing process performed during normal operation of thedistributed data storage system 400. Referring specifically to FIG. 5A,a flowchart of a computer-implemented method 500 for replicating thedata stored at a primary site to a cloud storage site is shown accordingto one embodiment. The method 500 may be performed in accordance withthe present invention in any of the environments depicted in FIGS. 1-4,among others, in various embodiments. Of course, more or less operationsthan those specifically described in FIG. 5 may be included in method500, as would be understood by one of skill in the art upon reading thepresent descriptions.

Each of the steps of the method 500 may be performed by any suitablecomponent of the operating environment. For example, in variousembodiments, the method 500 may be partially or entirely performed by acontroller, a processor, etc., or some other device having one or moreprocessors therein. The processor, e.g., processing circuit(s), chip(s),and/or module(s) implemented in hardware and/or software, and preferablyhaving at least one hardware component may be utilized in any device toperform one or more steps of the method 500. Illustrative processorsinclude, but are not limited to, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), etc., combinations thereof, or any other suitablecomputing device known in the art.

As shown in FIG. 5, operation 502 of method 500 includes initiallyperforming a scale out backup and restore (SOBAR) operation. A SOBARoperation provides a mechanism to backup metadata as well as inodeinformation which corresponds to the specific data (e.g., files) storedat the primary site. Accordingly, the SOBAR operation allows formetadata and inode information corresponding to the data stored at theprimary site to be copied to the cloud storage site. Once stored at thecloud storage site, this metadata and inode information may further berestored at another site in response to experiencing a disaster event atthe primary site, e.g., as will soon become apparent.

The metadata that is copied to the cloud storage site as a result ofperforming the SOBAR operation may vary depending on the desiredapproach. For instance, in some approaches the metadata includestimestamp information which indicates when particular data was created,last modified, read, etc. In other approaches, the metadata includesconfiguration information which pertains to how data is interrelated,e.g., as would be appreciated by one skilled in the art after readingthe present description.

The SOBAR operation is repeated periodically over time, e.g., such thatthe metadata and inode information is updated on the cloud storage siteto accurately reflect any changes that have been made to the data storedat the primary site. Accordingly, decision 504 includes determiningwhether a first predetermined amount of time has passed since a lastSOBAR operation was performed. The first amount of time may bepredetermined by a user, a system administrator, industry standards,etc.

In response to determining that the first predetermined amount of timehas passed since the last SOBAR operation was performed, method 500returns to operation 502 such that a subsequent SOBAR operation isperformed. However, in response to determining that the firstpredetermined amount of time has not passed since the last SOBARoperation was performed, method 500 proceeds to decision 506. There,decision 506 includes determining whether a second predetermined amountof time has passed since a last pre-migrate operation was performed.

A migrate operation involves tiering data stored at a first location toa second location. Referring momentarily back to the distributed storagesystem 400 of FIG. 4, a migrate operation performed on the primary site402 involves migrating the data (e.g., files) stored at the primary site402 to the cloud storage site 404. It follows that data which has beenmigrated from the primary site 402 now remains stored only at cloudstorage site 404, in turn achieving storage efficiency. Migrateoperations are also preferably performed periodically over time in orderto migrate any newly classified data stored at the primary site as it isadded to, amended, removed, etc. This second amount of time may also bepredetermined by a user, a system administrator, industry standards,etc., depending on the desired approach. Thus, between two full SOBARbackup windows, additional data is being tiered (e.g., migrated) to thecloud storage site 404.

In response to determining that the second predetermined amount of timehas not yet passed since a last pre-migrate operation was performed,method 500 returns to decision 504 as shown. It follows that decisions504 and 506 may be repeated in an iterative fashion until one or both oftheir respective conditions have been met. However, in response todetermining that the second predetermined amount of time has passedsince the last pre-migrate operation was performed, method 500 proceedsto operation 508.

There, operation 508 includes scanning the data stored at the primarysite for any malware that may be included therein. In other words,operation 508 includes scanning the primary site for any informationwhich is involved with and/or related to obtaining unauthorized accessto the primary site. Moreover, the data stored at the primary site isscanned for malware before being moved to the cloud storage site,thereby protecting the cloud storage site, and the overarching storagesystem itself, from cyberattacks.

In some approaches, operation 508 may be performed by scanning the datafor specific data sequences which are consistent with known types ofmalware. However, it should be noted that malware may be identifiedusing any type of scanning procedure which would be apparent to oneskilled in the art after reading the present description. In preferredapproaches, the scan performed in operation 508 is able to keep track ofwhat data has already been examined. In other words, an initial scan mayinvolve inspecting all data stored at the primary site, while subsequentscans only involve inspecting data which has been introduced and/ormodified since the last malware scan was performed. This desirablyreduces processing delays and system bandwidth consumption whilemaintaining robust protection against cyberattacks at the primary siteas well as the cloud storage site.

Method 500 further includes performing a migrate operation. Seeoperation 510. As mentioned above, a migrate operation involves movingthe data stored at a first location (e.g., primary site) to a secondlocation (e.g., cloud storage site). This data movement results inzero-byte file stubs being left at the primary site, each stubcorresponding to a respective portion of the migrated data. The migrateddata itself resides at a cloud storage site, thereby removing the desireof maintaining two copies of data. High availability and redundancy of acloud storage site (e.g., see 404 above) is also leveraged in someapproaches to further protect the data.

From operation 510, method 500 returns to decision 504, whereby anotherdetermination may be made as to whether the first predetermined amountof time has passed since the last SOBAR operation was performed. Asalluded to above, various ones of the processes included in method 500are repeated in an iterative process during nominal operation of thecorresponding distributed data storage system.

Referring momentarily now to FIG. 5B, an illustrative progression ofbacking up (e.g., tiering) the data at a primary site to a cloud storagesite is depicted in accordance with an in-use example, which is in noway intended to limit the invention. As shown, the progression beginswith a SOBAR operation which is performed at t0. As mentioned above, theSOBAR operation involves the inode information as well as metadata(e.g., configuration information) which corresponds to the data storedat the primary site. Moreover, the inode information and metadata aresent directly to the cloud storage site, and not the disaster recoverysite. Compared to the data storage footprint of actual data, the storagecapacity consumed by this inode information and other metadata issignificantly smaller.

A second SOB AR operation is also in the process of being performed att5, and therefore has not yet been uploaded to the cloud storage site.Between the SOBAR operations, a number of migrate operations are alsoperformed. As mentioned above, the data at the primary site ispreferably scanned prior to actually performing each of the migrateoperations. According to an exemplary approach, a watcher programtriggers the performance of a “local_threat_scan” program which scansthe managed filesystem as well as the resident files to determine if anymalware exists therein.

Thereafter, the watcher program actually initiates migration of thefiles to the cloud storage site. As a result, each of the migrateoperations are performed such that whenever a new file is created ormodified in the filesystem, the watcher program ensures that none of thedata sent to the cloud storage site is infected by one or more softwareviruses. This also desirably ensures that the files which are migratedto the cloud storage site are resilient against cyberattacks, in turnthe cloud storage site (e.g., see 404 above) acts as an air-gap, orcyber resilient site. It should be noted that in some approaches, thewatcher program is a daemon which monitors the data creation and/ormodification, while also assisting with the migrate operations.Accordingly, whenever files are created, removed, modified, etc., thesame operations are replicated on the copy at the cloud storage site. Insome approaches, the watcher program is performed on cluster nodes.Moreover, the restore of primary site nodes can occur across differentclustered filesystem configurations and a pre-load of the respectiveimage is maintained in place for restoring nodes at the disasterrecovery site, e.g., as would be appreciated by one skilled in the artafter reading the present description.

In response to the watcher program completing the migrate operation, ajournal backup to the cloud storage site is executed. As a result, ifany data is migrated to cloud between two backup process using highercut-fast thread frequency, transparent cloud tiering may be used to pushjournal chunks quickly to the cloud storage site, e.g., as would beappreciated by one skilled in the art after reading the presentdescription. This also desirably reduces the backup window, therebyreducing the chance of experiencing a backlog, and increasing RPO(recovery point objective). According to an example, which is in no wayintended to limit the invention, a migrate operation performed at t1results in 100 files being migrated between t0 and t1. Accordingly, adisaster which occurs between t1 and t2 while a next 100 files are beingpre-migrated will desirably not affect the data which was pre-migratedbetween t0 and t1.

It follows that during nominal operation of a distributed data storagesystem (e.g., see FIG. 4), the various processes in method 500 are ableto achieve an accurate backup of the primary site. This SOBAR backupmainly consists of inode information and metadata of all the files inthe filesystem. With this information, only a single copy of data, inodeinformation, metadata plus delta inode information between time t0 andt1 is now available at the cloud storage site. Moreover, this backupcopy of the primary site is stored in a cloud storage site, which isparticularly desirable because cloud storage provides a much more easilyscalable data storage platform, e.g., in comparison to the disasterrecovery site. Accordingly, the disaster recovery site remains idlewhile the primary site and the cloud storage site are operatingnominally. However, it should be noted that the disaster recovery siteis in no way required to remain completely idle. For instance, thedisaster recovery site may be utilized to provide additional computingpower during periods of high latency.

Although method 500 is able to achieve an accurate backup of the primarysite during normal operating conditions, For example, the primary sitemay experience a disaster situation such as a power outage, a naturaldisaster, an unintentional shutdown, etc. Although the cloud storagesite contains a copy of the data stored at the primary site prior to itgoing offline, it is not practical to shift operational control of theoverarching data storage system to the cloud storage site. Rather, it ispreferred that the disaster recovery site assume operational control ofthe data storage system, at least while the primary site remainsoffline.

As mentioned above, the disaster recovery site remains idle while theprimary site is operational, and therefore the disaster recovery sitedoes not accurately reflect the filesystems at the primary site. The actof transferring all the information and data from the cloud storage siteto the disaster recovery site may thereby seem like a logical steptowards making the data storage system operational again, but themonetary, computing, temporal, etc., costs associated with doing so aresevere. Rather, FIG. 6A illustrates a flowchart of acomputer-implemented method 600 for bringing a disaster recovery siteonline, according to one embodiment. The method 600 may be performed inaccordance with the present invention in any of the environmentsdepicted in FIGS. 1-5B, among others, in various embodiments. Of course,more or less operations than those specifically described in FIG. 6A maybe included in method 600, as would be understood by one of skill in theart upon reading the present descriptions.

Each of the steps of the method 600 may be performed by any suitablecomponent of the operating environment. For example, in variousembodiments, the method 600 may be partially or entirely performed by acontroller, a processor, etc., or some other device having one or moreprocessors therein. The processor, e.g., processing circuit(s), chip(s),and/or module(s) implemented in hardware and/or software, and preferablyhaving at least one hardware component may be utilized in any device toperform one or more steps of the method 600. Illustrative processorsinclude, but are not limited to, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), etc., combinations thereof, or any other suitablecomputing device known in the art.

As shown in FIG. 6A, operation 602 of method 600 includes mounting apre-inode list filesystem. Again, the disaster recovery site remainsidle during nominal operation of the overarching distributed datastorage system, and therefore a general filesystem is first mounted. Thepre-inode list filesystem may be mounted in read only mode in someapproaches, while in other approaches the filesystem may also oralternatively support writes.

Operation 604 further includes enabling cloud tiering functionality. Insome approaches, the cloud tiering functionality is enabled byinstalling packages which correspond thereto, e.g., as would beappreciated by one skilled in the art after reading the presentdescription. For example, a package containing a Spectrum Scalefilesystem edition which supports cloud tiering functionality may beselectively installed, e.g., by a user.

Moreover, operation 606 includes receiving a transparent cloud tieringbackup file from the cloud storage site. The transparent cloud tieringbackup file which is received is often a copy of a file which exists atthe cloud storage site. However, because the transparent cloud tieringbackup file is typically a small file, the copy of this files is formedin a desirably small amount of time (e.g., within a few minutes). Itshould also be noted that a transparent cloud tiering backup file is inno way intended to limit the invention. Rather, in other approaches adifferent type of file or packet of information may be received inoperation 606, e.g., as would be appreciated by one skilled in the artafter reading the present description.

Network shared disks are also pre-created at the disaster recovery sitefor the filesystem in some approaches. In such approaches, the networkshared disks may be pre-created using any procedures which would beapparent to one skilled in the art after reading the presentdescription. Moreover, the network shared disks preferably match innumber and configuration as those included at the primary site in orderto achieve a successful restore at the disaster recovery site.

Operation 608 includes executing a transparent cloud tiering restore. Inpreferred approaches, the transparent cloud tiering restore is executedby specifying a particular access point at the cloud storage site. Indoing so, the disaster recovery site is able to communicate directlywith the cloud storage site and receive specific data, inodeinformation, metadata, etc. therefrom, e.g., as will soon becomeapparent.

Once the transparent cloud tiering restore has been performed, theoperational relationship previously shared between the primary site andthe cloud storage site is restored between the disaster recovery siteand the cloud storage site. In some approaches, a corresponding sharingcontainer is only presented in an “ONLINE” state, thereby allowing anadministrator to download desired data (e.g., files) from the cloudstorage site. It is preferred that the disaster recovery site implementsa same number of cloud storage access point IPs as were implemented atthe primary site. However, a different number of cloud storage accesspoint IPs may be implemented in some approaches. In such approaches, itshould be noted that while the number of cloud storage access point IPsfor the disaster recovery site is different than implemented by theprimary site, the number of cloud storage access point uniform resourcelocators (URLs) used preferably matches the number of cloud storageaccess point URLs used at the primary site. However, in situations wherefewer cloud storage access point URLs are implemented at the disasterrecovery site than the primary site, one or more of the URL and IPcombinations may be repeated, e.g., as would be appreciated by oneskilled in the art after reading the present description.

As mentioned above, the various processes included in method 600 areperformed in response to the primary site going offline (e.g.,experiencing a disaster event). Accordingly, the cloud storage site'sbackup copy of the data that is stored at the primary site may beutilized to bring the disaster recovery site online. Referring still toFIG. 6A, operation 610 includes receiving an inode list from the cloudstorage site, while operation 612 includes receiving configurationinformation from the cloud storage site. The inode list and/or theconfiguration information are received from the access point specifiedas a part of executing the transparent cloud tiering restore inoperation 608 above. Again, by specifying a particular access point atthe cloud storage site, the disaster recovery site is able tocommunicate directly with the cloud storage site and receive specificdata, inode information, metadata, etc. therefrom.

The inode list and the configuration information are further used toconstruct a filesystem at the disaster recovery site. See operation 614.However, it should be noted that the filesystem constructed at thedisaster recovery site does not include an actual copy of the data thatis stored at the cloud storage site. In other words, data is notautomatically copied from the cloud storage site to the filesystemcreated at the disaster recovery site. Rather, the filesystem created atthe disaster recovery site includes a plurality of metadata stubs. Eachof these metadata stubs corresponds to a specific portion of data (e.g.,file) which is stored at the primary site as well as the cloud storagesite. The actual information included in each of the metadata stubs mayvary depending on the desired approach. For instance, in variousapproaches each of the metadata stubs may include the name, logicalblock address, physical block address, total size (e.g., number ofbytes), etc., of the file (or portion of a file) which correspondsthereto. It follows that the metadata stubs themselves consume only afraction of the storage space that the actual data corresponding theretodoes. Accordingly, the filesystem constructed in operation 614significantly improves storage space utilization at the disasterrecovery site.

In some approaches, the inode list and the configuration information areused to construct a filesystem at the disaster recovery site byperforming a SOBAR operation. Accordingly, operation 614 may includedownloading a SOBAR configuration backup and/or an inode backup from thecloud storage site. Accordingly, a SOBAR restore operation may beexecuted for each of the filesystems that are restored at the disasterrecovery site. However, additional filesystem related commands are notrepeated at the disaster recovery site, as only metadata stubs have beenrestored in preferred approaches.

Moreover, while performing a SOBAR restore operation, a priority indexprocess scans through the journal and metadata in some approaches todetermine which metadata should be restored on the priority basis. Afile curation operation is also triggered in some approaches whichconverts co-resident files into non-resident when restored at thedisaster recovery site. In other words, operation 614 actually includesexamining each entry in the inode list at the disaster recovery site,and converting co-resident entries to non-resident entries. With respectto the present description, “co-resident entries” represent data (e.g.,files) that have been migrated from the given filesystem to the cloudstorage site, but which also remain available on the given filesystem aswell. Moreover, “non-resident entries” represent data (e.g., files) thathave been migrated from a given filesystem to the cloud storage site,while only a metadata stub remains on the given filesystem. It followsthat some of the entries in the inode list are non-resident where onlyone copy of data is available on cloud storage site. Some of the entriesin the inode list at the primary site are co-resident entries and all ofthe data at the primary site is copied to the cloud storage site forsuch co-resident entries. Moreover, each of the entries in the inodelist which corresponds to the disaster recovery site are non-residententries. This is because while the cloud storage site contains an actualcopy of the data that is stored at the offline primary site, thedisaster recovery site only includes metadata stubs, each of whichcorrespond to a specific portion of the data at the cloud storage site.

The filesystem constructed at the disaster recovery site is thereby usedto satisfy I/O commands that are received. See operation 616.Specifically, the metadata stubs in the filesystem constructed at thedisaster recovery site are used in combination with the data copiesstored at the cloud storage site to satisfy I/O commands that arereceived, e.g., from a user communicating with the primary site prior toit going offline. Looking to FIG. 6B, exemplary sub-processes of usingthe filesystem constructed at the disaster recovery site to satisfyreceived I/O commands are illustrated in accordance with one embodiment,one or more of which may be used to perform operation 616 of FIG. 6A.However, it should be noted that the sub-processes of FIG. 6B areillustrated in accordance with one embodiment which is in no wayintended to limit the invention.

As shown, the flowchart includes actually receiving an I/O command. Seesub-operation 620. The I/O command that is received may vary dependingon the approach. For instance, the I/O command may be a read command, awrite command, a read-modify command, etc. Moreover, sub-operation 622includes identifying a portion of the data that is stored at the primarysite which the I/O command corresponds to. An I/O command typicallyidentifies the specific data (e.g., file or portion thereof) which isinvolved. Thus, the information provided in the I/O itself may be usedin some approaches to identify the specific portion of data insub-operation 622. In other approaches, sub-operation 622 involvesexamining the inode list at the disaster recovery site in order toidentify a specific portion of the data which the I/O commandcorresponds to.

Sub-operation 624 further includes identifying one or more of themetadata stubs which correlate to the portion of the data that is storedat the primary site. In other words, sub-operation 624 includesidentifying one or more of the metadata stubs at the disaster recoverysite which correlate to the portion of the data (e.g., file) identifiedin the received I/O command. Once the one or more metadata stubs at thedisaster recovery site have been identified, sub-operation 626 includesusing the one or more identified metadata stubs to send a request to thecloud storage site for a copy of the respective data.

The copy of the data stored at the primary site is received insub-operation 628 from the cloud storage site in response to the requestsent in sub-operation 626. Moreover, sub-operation 630 includes storingthe received data in the filesystem at the disaster recovery site. Inother words, the data received from the cloud storage site actuallyreplaces the metadata stubs at the disaster recovery site whichcorrespond thereto. Furthermore, sub-operation 632 includes actuallyusing the received copy of the data to satisfy the I/O command.

By only copying the data which corresponds to received I/O commands,various ones of the embodiments included herein are able to achieve asignificant reduction in the processing delays, storage space, networkbandwidth consumption, etc. experienced in response to a disaster eventoccurring at the primary storage site. This is achieved, at least inpart, because the metadata stubs at the disaster recovery site consumeonly a fraction of the storage space that the actual data correspondingthereto does. Accordingly, the filesystem constructed at the disasterrecovery site significantly improves storage space utilization, and evenallows for the disaster recovery site to be scaled accordingly, therebyreducing operating costs.

Moreover, communication bandwidths between the different sites in thedistributed data storage system are not excessively taxed as inode listsand configuration information are small in size. Additionally, only datawhich specifically corresponds to received I/O commands is transferredbetween the cloud storage site and the disaster recovery site, therebyfurther reducing network traffic and operating expenses while alsoavoiding network degradation and related performance issues. The datathat is copied from the cloud storage site to the disaster recovery sitewhile the primary site remains offline is maintained at the disasterrecovery site in some approaches, e.g., such that it remains availableat the disaster recovery site for any subsequent I/O commands whichcorrespond thereto.

A primary site which has gone offline, e.g., in response to experiencinga disaster event, may eventually be brought back online. In someapproaches, the operational control of the data storage system may bereturned to the primary site in response to it coming back online byreplicating any data modifications which were performed at the disasterrecovery site while the primary site was offline. However, in otherapproaches the disaster recovery site may retain operational control ofthe data storage system until system throughput falls below apredetermined threshold, a predetermined amount of time has passed,computing and/or network bandwidth consumption rises above apredetermined threshold, etc.

It should also be noted that although various ones of the embodimentsincluded herein are described in the context of a distributed datastorage system which includes a primary site, a cloud storage site, anda disaster recovery site (e.g., as shown in FIG. 4 above), this is in noway intended to limit the invention. Rather, any of the approachesdescribed herein may be implemented similarly in a distributed datastorage system which includes any number of data storage sites.

According to an in-use example, which is in no way intended to limit theinvention, a customer has four data storage sites which are divided intoCluster 1 which includes Primary Site 1 and Primary Site 2, and Cluster2 which includes Disaster Recovery Site 3 and Disaster Recovery Site 4.Additionally, a Cloud Storage Site is coupled to each of the clusters.The distance between Cluster 1 and Cluster 2 is more than 700kilometers. Additionally, Primary Site 1 and Primary Site 2 include “n”different filesystems which are to be protected from data loss. TheCloud Storage Site accessor node connected to Cluster 1 is differentfrom the Cloud Storage Site accessor node that is connected to Cluster2. Accordingly, accessors 1-4 are enabled at Primary Site 1 andaccessors 4-8 are disabled at Disaster Recovery Site 3 while thedisaster recovery sites at Cluster 2 remain idle during nominaloperation. However, in response to the primary sites going offline atCluster 1 (e.g., in response to a disaster event occurring), accessors4-8 at Disaster Recovery Site 3 are preferably enabled and used torestore the metadata on the disaster recovery site from the cloudstorage site using any of the approaches included herein. Accordingly,only metadata stubs will be present on the filesystem at the disasterrecovery sites. However, when each of these stubs are accessed inresponse to receiving an I/O command, the data which corresponds theretois transparently recalled from the cloud storage site.

It is understood in advance that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 7, a schematic of an example of a cloud computingnode is shown. Cloud computing node 700 is only one example of asuitable cloud computing node and is not intended to suggest anylimitation as to the scope of use or functionality of embodiments of theinvention described herein. Regardless, cloud computing node 700 iscapable of being implemented and/or performing any of the functionalityset forth hereinabove.

In cloud computing node 700 there is a computer system/server 702, whichis operational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 702 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 702 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 702 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 7, computer system/server 702 in cloud computing node700 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 702 may include, but are notlimited to, one or more processors or processing units 706, a systemmemory 728, and a bus 708 that couples various system componentsincluding system memory 728 to processor 706.

Bus 708 represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Computer system/server 702 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 702, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 728 can include computer system readable media in the formof volatile memory, such as random access memory (RAM) 730 and/or cachememory 732. Computer system/server 702 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 734 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 708 by one or more datamedia interfaces. As will be further depicted and described below,memory 728 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 740, having a set (at least one) of program modules 742,may be stored in memory 728 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 742 generally carry out the functionsand/or methodologies of embodiments of the invention as describedherein.

Computer system/server 702 may also communicate with one or moreexternal devices 704 such as a keyboard, a pointing device, a display724, etc.; one or more devices that enable a user to interact withcomputer system/server 702; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 702 to communicate withone or more other computing devices. Such communication can occur viaI/O interfaces 722. Still yet, computer system/server 702 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 720. As depicted, network adapter 720communicates with the other components of computer system/server 702 viabus 708. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 702. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

Referring now to FIG. 8, illustrative cloud computing environment 850 isdepicted. As shown, cloud computing environment 850 includes one or morecloud computing nodes 810 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 854A, desktop computer 854B, laptop computer 854C,and/or automobile computer system 854N may communicate. Nodes 810 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 850 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 854A-854Nshown in FIG. 8 are intended to be illustrative only and that computingnodes 810 and cloud computing environment 850 can communicate with anytype of computerized device over any type of network and/or networkaddressable connection (e.g., using a web browser).

Referring now to FIG. 9, a set of functional abstraction layers providedby cloud computing environment 850 (FIG. 8) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 9 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 960 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 961;RISC (Reduced Instruction Set Computer) architecture based servers 962;servers 963; blade servers 964; storage devices 965; and networks andnetworking components 966. In some embodiments, software componentsinclude network application server software 967 and database software968.

Virtualization layer 970 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers971; virtual storage 972; virtual networks 973, including virtualprivate networks; virtual applications and operating systems 974; andvirtual clients 975.

In one example, management layer 980 may provide the functions describedbelow. Resource provisioning 981 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 982provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may include applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 983 provides access to the cloud computing environment forconsumers and system administrators. Service level management 984provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 985 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 990 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 991; software development and lifecycle management 992;virtual classroom education delivery 993; data analytics processing 994;transaction processing 995; and restoring operation of a data storagesystem at an idol disaster recovery site using inode lists andconfiguration information 996.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a LAN or a WAN, or the connection may be madeto an external computer (for example, through the Internet using anInternet Service Provider). In some embodiments, electronic circuitryincluding, for example, programmable logic circuitry, field-programmablegate arrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instructions by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Moreover, a system according to various embodiments may include aprocessor and logic integrated with and/or executable by the processor,the logic being configured to perform one or more of the process stepsrecited herein. The processor may be of any configuration as describedherein, such as a discrete processor or a processing circuit thatincludes many components such as processing hardware, memory, I/Ointerfaces, etc. By integrated with, what is meant is that the processorhas logic embedded therewith as hardware logic, such as an applicationspecific integrated circuit (ASIC), a FPGA, etc. By executable by theprocessor, what is meant is that the logic is hardware logic; softwarelogic such as firmware, part of an operating system, part of anapplication program; etc., or some combination of hardware and softwarelogic that is accessible by the processor and configured to cause theprocessor to perform some functionality upon execution by the processor.Software logic may be stored on local and/or remote memory of any memorytype, as known in the art. Any processor known in the art may be used,such as a software processor module and/or a hardware processor such asan ASIC, a FPGA, a central processing unit (CPU), an integrated circuit(IC), a graphics processing unit (GPU), etc.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer to offer service on demand.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A computer-implemented method for restoringoperation of a data storage system at a disaster recovery site,comprising: in response to a disaster event occurring at a primary site,receiving an inode list from a cloud storage site, wherein the cloudstorage site includes a backup copy of data that is stored at theprimary site; receiving configuration information from the cloud storagesite; using the inode list and the configuration information toconstruct a filesystem at the disaster recovery site, wherein thefilesystem at the disaster recovery site does not include a copy of thedata that is stored at the primary site, wherein the filesystem includesa plurality of metadata stubs; and using the filesystem to satisfyinput/output (I/O) commands that are received.
 2. Thecomputer-implemented method of claim 1, wherein using the filesystem tosatisfy I/O commands that are received includes: receiving an I/Ocommand; identifying a portion of the data that is stored at the primarysite which the I/O command corresponds to; identifying one or more ofthe metadata stubs which correlate to the portion of the data that isstored at the primary site; using the one or more identified metadatastubs to send a request to the cloud storage site for a copy of theportion of the data that is stored at the primary site; receiving thecopy of the portion of the data that is stored at the primary site; andusing the received copy of the portion of the data that is stored at theprimary site to satisfy the I/O command.
 3. The computer-implementedmethod of claim 1, wherein the backup copy of the data that is stored atthe primary site is scanned for malware before being stored at the cloudstorage site.
 4. The computer-implemented method of claim 1, comprising:examining each entry in the inode list; and converting co-residententries to non-resident entries.
 5. The computer-implemented method ofclaim 1, comprising: mounting a pre-inode list filesystem; enablingcloud tiering functionality; receiving a transparent cloud tieringbackup file from the cloud storage site; and executing a transparentcloud tiering restore by specifying an access point at the cloud storagesite, wherein the inode list and the configuration information arereceived from the specified access point.
 6. The computer-implementedmethod of claim 5, wherein the pre-inode list filesystem is mounted inread only mode.
 7. The computer-implemented method of claim 1, whereinusing the inode list and the configuration information to construct thefilesystem at the disaster recovery site includes: performing a scaleout backup and restore operation.
 8. A computer program product forrestoring operation of a data storage system at a disaster recoverysite, the computer program product comprising a computer readablestorage medium having program instructions embodied therewith, theprogram instructions readable and/or executable by a processor to causethe processor to: in response to a disaster event occurring at a primarysite, receive, by the processor, an inode list from a cloud storagesite, wherein the cloud storage site includes a backup copy of data thatis stored at the primary site; receive, by the processor, configurationinformation from the cloud storage site; use, by the processor, theinode list and the configuration information to construct a filesystemat the disaster recovery site, wherein the filesystem at the disasterrecovery site does not include a copy of the data that is stored at theprimary site, wherein the filesystem includes a plurality of metadatastubs; and use, by the processor, the filesystem to satisfy input/output(I/O) commands that are received.
 9. The computer program product ofclaim 8, wherein using the filesystem to satisfy I/O commands that arereceived includes: receiving an I/O command; identifying a portion ofthe data that is stored at the primary site which the I/O commandcorresponds to; identifying one or more of the metadata stubs whichcorrelate to the portion of the data that is stored at the primary site;using the one or more identified metadata stubs to send a request to thecloud storage site for a copy of the portion of the data that is storedat the primary site; receiving the copy of the portion of the data thatis stored at the primary site; and using the received copy of theportion of the data that is stored at the primary site to satisfy theI/O command.
 10. The computer program product of claim 8, wherein thebackup copy of the data that is stored at the primary site is scannedfor malware before being stored at the cloud storage site.
 11. Thecomputer program product of claim 8, the program instructions readableand/or executable by the processor to cause the processor to: examine,by the processor, each entry in the inode list; and convert, by theprocessor, co-resident entries to non-resident entries.
 12. The computerprogram product of claim 8, the program instructions readable and/orexecutable by the processor to cause the processor to: mount, by theprocessor, a pre-inode list filesystem; enable, by the processor, cloudtiering functionality; receive, by the processor, a transparent cloudtiering backup file from the cloud storage site; and execute, by theprocessor, a transparent cloud tiering restore by specifying an accesspoint at the cloud storage site, wherein the inode list and theconfiguration information are received from the specified access point.13. The computer program product of claim 12, wherein the pre-inode listfilesystem is mounted in read only mode.
 14. The computer programproduct of claim 8, wherein using the inode list and the configurationinformation to construct the filesystem at the disaster recovery siteincludes: performing a scale out backup and restore operation.
 15. Asystem, comprising: a processor; and logic integrated with theprocessor, executable by the processor, or integrated with andexecutable by the processor, the logic being configured to: in responseto a disaster event occurring at a primary site, receive, by theprocessor, an inode list from a cloud storage site, wherein the cloudstorage site includes a backup copy of data that is stored at theprimary site; receive, by the processor, configuration information fromthe cloud storage site; use, by the processor, the inode list and theconfiguration information to construct a filesystem at a disasterrecovery site, wherein the filesystem at the disaster recovery site doesnot include a copy of the data that is stored at the primary site,wherein the filesystem includes a plurality of metadata stubs; and use,by the processor, the filesystem to satisfy input/output (I/O) commandsthat are received.
 16. The system of claim 15, wherein using thefilesystem to satisfy I/O commands that are received includes: receivingan I/O command; identifying a portion of the data that is stored at theprimary site which the I/O command corresponds to; identifying one ormore of the metadata stubs which correlate to the portion of the datathat is stored at the primary site; using the one or more identifiedmetadata stubs to send a request to the cloud storage site for a copy ofthe portion of the data that is stored at the primary site; receivingthe copy of the portion of the data that is stored at the primary site;and using the received copy of the portion of the data that is stored atthe primary site to satisfy the I/O command.
 17. The system of claim 15,wherein the backup copy of the data that is stored at the primary siteis scanned for malware before being stored at the cloud storage site.18. The system of claim 15, the logic being configured to: examine, bythe processor, each entry in the inode list; and convert, by theprocessor, co-resident entries to non-resident entries.
 19. The systemof claim 15, the logic being configured to: mount, by the processor, apre-inode list filesystem; enable, by the processor, cloud tieringfunctionality; receive, by the processor, a transparent cloud tieringbackup file from the cloud storage site; and execute, by the processor,a transparent cloud tiering restore by specifying an access point at thecloud storage site, wherein the inode list and the configurationinformation are received from the specified access point, wherein thepre-inode list filesystem is mounted in read only mode.
 20. The systemof claim 15, wherein using the inode list and the configurationinformation to construct the filesystem at the disaster recovery siteincludes: performing a scale out backup and restore operation.